Measuring the Severity of Chronic Kidney Disease

How do we tell how severe a person’s kidney disease is? One of the most common tools is the estimated glomerular filtration rate (eGFR). This test looks at the level of creatine in your blood. It’s one of the waste products that your kidneys are supposed to filter out, so if you have more creatine in your blood, then your filtration rate is likely poor.

The advantage of eGFR is that it gives us a good single number to look at that we can compare to set standards. An eGFR of 60 or more is considered normal. By the time the eGFR drops below 15, people need to get dialysis or consider getting a kidney transplant.

People with Sleep Apnea Have More Severe Disease

For this study, researchers looked at 269 people with stage 3or 4 chronic kidney disease. Of these 269, 121 had sleep apnea (45%–79 had mild sleep apnea and 42 had moderate or severe sleep apnea). They looked at numerous characteristics for all the subjects, including their eGFR. It was shown that people with sleep apnea had lower eGFR than those without. People with no sleep apnea had an average eGFR of 35.7, compared to 31.2 for those with mild and 26.5 for those with moderate or severe sleep apnea.

Sleep Apnea Treatment Helps

Next, they divided the people with sleep apnea up randomly to either get CPAP or not. Then they checked in with all patients after a year to see how their disease had progressed.

For all patients, eGFR fell. For people without sleep apnea, it fell by about 2.24. All people with sleep apnea saw greater declines than that, regardless of treatment. However, when patients got treatment, their declines were much less. For people with untreated mild sleep apnea, the decline was 3.54, but with treatment, the decline was only 2.84. For people with untreated moderate or severe sleep apnea, the decline was 5.97, but with treatment, the decline was only 3.14. All the improvements with treatment were statistically significant.

Early Intervention Is Best

While it can seem discouraging to note that sleep apnea treatment only slowed the progression of chronic kidney disease, it’s important to remember that these people were already in the advanced stages of the disease. In fact, all of these patients were newly diagnosed with sleep apnea, though their average age was almost 70. We don’t know how long the condition had been contributing to kidney damage. Twenty years? Fifty? By this time, much damage was already done, as shown by the greater severity of their disease at the start of the study.

We take this as a sober reminder that if you suspect sleep apnea, it’s important to talk to a doctor or a sleep dentist and get diagnosis and treatment as soon as possible, before too much damage is done.

If you think you might have sleep apnea, please, let us help. Don’t let damage continue any longer than necessary. To learn more about sleep apnea diagnosis, please call (402) 493-4175 today for an appointment with a sleep dentist at the Advanced Dental Sleep Treatment Center in Omaha.